I extracted plant samples with DMSO. To be able to calculate the yield, I have to separate the DMSO from the extract. Dissociation of DMSO in the evaporator is unlikely. Is there a different separation technique?
Lyophilization is the simplest and most efficient way, as you did. If not efficient enough on first try, just dilute your sample with some water and freeze-dry again, and repeat once more if necessary.